Patent GB-188696-A (GB)
Title: Improvements in or relating to apparatus for use in indicating or recording changes in the velocity or path of travel of aircraft or under-water craft, said apparatus being also applicable to the stabilising, directing or control of such craft
IPC: G01C21/00
Filed: 1921-06-10
Abstract: 188,696. Vickers, Ltd., and Wearham, J. June 10, 1921. Clinometers; course-recording apparatus; bearings, indicating.-In apparatus for indicating, recording, or utilizing changes in the magnitude or direction of the velocity of an aircraft or submarine, a succession of bodies falling under gravity, and free from impressed forces except those due to the movement of the craft, is observed directly or is arranged to actuate indicating or recording devices or devices for stabilizing, directing, or controlling the craft. Fig. 1 shows an apparatus in whch a succession of falling drops of mercury indicates directly the changes in velocity. A glass vessel A is formed with upper and lower containers A<1> for mercury each provided with a duct A<2> leading to 'diametrically-opposite points on a sleeve A<3> which is rotatable on a hollow support C fixed to the craft to bring one or other of the containers A<1> into the upper position in which the mercury flows down the corresponding duct A<2> and through a tube C<1> within the support C. The tube C<1> discharges through a restricted orifice into a bulb C<2> provided with a nozzle C<3> which is normally directed vertically downwards. The mercury falls in a succession of drops into a passage A<4> and thence flows through an outlet A<5> into the lower container A<1>. A lamp D, which illuminates the falling drops, is in circuit with contacts B<1> in the upper duct A<2> so that when the level of the mercury falls below these contacts the fact is indicated by the extinguishing of the lamp. Two pairs of cross-wires E are disposed in the vessel A with their points of intersection normally in vertical line with the nozzle C<3>. The vessel A may be exhausted through a pipe C<5>. Any change of velocity is indicated by a deviation of the line of falling drops from the point of intersection of the lower crosswires. In a modification Figs. 3 and 4, the falling bodies are constituted by balls F of steel, agate, or other hard material. A drum G is rotated about a second 'drum H which is fixed to the craft and provided with a tube H' containing a column of the balls. The balls are released individually in rapid succession in the following manner. The lowermost 'ball is retained by the lower ends of three arms L pivoted to the tube H<2> until these arms are operated from a cam J<1> to release it, whereupon it is retained, free from the weight of the balls above it, by the lower ends of three similar arms K until these in turn are operated from the cam to allow the ball to fall freely. The arms K, L are each pressed outwardly by a spring to cause a roller K<1> or L<1> carried by the arm to bear against the cam J' shaped as shown in Fig. 4 and rotated through bevel gearing G<2>, J from the drum G. The drum H carries in its lower part a series of parallel fine wires M spaced to a distance slightly less than the diameter of a ball and connected at one end to a common conductor M<1>, Fig. 5. The other end of each wire is connected by a spring M<2> to a bar M<3>, and carries a contact strip M<4> disposed adjacent to a corresponding contact strip M<5> carried by a bar M<4>. Each ball falling on a wire 'displaces the wire sufficiently to allow the ball to fall through the grid and to cause the strip M<6> to contact with the corresponding strip M<5> to complete a circuit through a corresponding indicator lamp or recording device or through electrical devices for automatically controlling the craft. The balls fall on to strips H<3> from which they roll into the drum G to be elevated by the ribs G<3> into the. tube H<2>. The apparatus may be arranged to control the speed of a chronometer to obtain an indication of the distance travelled, or may be used for moving a map in relation to a pointer to indicate the location of the craft. To indicate rate of change of angular position of the craft, two of the instruments shown in Figs. 3 and 4 are used, one at each end or side of the craft, and are synchronized to release the balls simultaneously, so that when a change of angular position occurs, its rate is indicated by the difference between the times at which the balls in the two instruments make the contacts.